High Performance Troffers
Office Lighting Troffers, Fluorescent: Volumetric vs. Parabolic
Good quality design of fluorescent fixtures provides more effective use of lighting, potentially allowing using lower light levels and encouraging installation of high-quality, high-performance fluorescent lighting, especially as a replacement for parabolic fixtures.
Item ID: 129
Technical Advisory Group: 2009 Lighting TAG (#1)
Overhead lighting presents the challenge of providing adequate lighting while reducing glare. In the computer era, this is especially difficult due to reflections off computer monitor screens. Lithonia introduced the RT5 volumetric lighting fixtures in 2004 as a solution to this issue. These fixtures spread light evenly throughout a space, functioning both with surface or recessed mounting. The fixtures correct for many problems of its popular predecessor, the parabolic fixture. These problems include “cave effect,” harsh shadows, and low fixture efficiency (~65%).
Volumetric lighting is achieved by integrating lamp shielding and using Fresnel reflection to diffuse the compact brightness of the T5 lamp it uses. Luminaire efficiency should be well above 70%. Significant energy savings are achieved over T12 and T8 systems, and further enhanced if combined with dimming. Kits are available to convert existing fixtures to this distribution, and LED source fixtures are also available.
Baseline Description: Standard office lighting
Baseline Energy Use: 3 kWh per year per square foot
The baseline value is based on office lighting, with a baseline of the WA energy code standard of 1 W/sf, in office lighting, operating 3000 hrs. per year.
Manufacturer's Energy Savings Claims:
Currently no data available.
Best Estimate of Energy Savings:
"Typical" Savings: 15%
Energy Savings Reliability: 4 - Extensive Assessment
Efficiency based on replacing a 65% efficient luminaire with a 75% efficient luminaire.
Energy Use of Emerging Technology:
2.6 kWh per square foot per year
Energy Use of an Emerging Technology is based upon the following algorithm.
Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
Potential number of units replaced by this technology:
Office space only. Commercial Building Stock Assessment, NEEA, 2009 http://neea.org/resource-center/regional-data-resources/commercial-building-stock-assessment
Regional Technical Potential:
0.27 TWh per year
Regional Technical Potential of an Emerging Technology is calculated as follows:
Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Currently no data available.
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.